This invention pertains to machines for making packages from web material, and deals more particularly with a sealing mechanism for use in such a machine for sealing at least two layers of a body of web material to one another as the web material is moved through the machine.
In package making machines, it is quite common to form seals in web material by two sealing jaws which in a seal-making cycle from a relatively open condition move to a closed condition at which the web material is squeezed therebetween. During the closed state of the jaws, the seal may be formed in various different ways as by applying heat from one or the other or both of the jaws to a heat sealable web material, by applying the pressure of the jaws to a pressure sensitive web material, or by applying clips, staples, bands, adhesive strips or other fasteners to the material. The present invention concerns primarily an apparatus or mechanism for operating such sealing jaws and may be used in various different types of package making machines and for making various different forms of seals. By way of example, the mechanism as shown herein is part of a vertical forming, filling and sealing packaging machine for making package end seals, but it will be understood that the invention in its broader aspects is not limited to this particular application.
The general object of this invention is to provide a sealing mechanism for a web fed package making machine including two sealing jaws capable of being cyclicly moved between opened and closed conditions and which sealing mechanism is of a simple, low cost and reliable construction.
A further object of the invention is to provide a sealing mechanism wherein the sealing jaws are moved smoothly into their closed condition and in such closed condition are held against reverse or opening movement by an extremely high force.
Another object of the invention is to provide a jaw-type sealing mechanism for a package making machine wherein a crank and connecting link is used to drive the two jaws between their opened and closed conditions and wherein the parts of such driving arrangement are of relatively small size and located so as to be generally out of the way with regard to the machine operator thereby making the associated sealing station of the machine readily open and accessible to the operator.
Another object of the invention is to provide a sealing mechanism of the foregoing character which easily may be made as a module that can be removed from the machine and replaced by another similar module or that can be shifted to different positions relative to the remainder of the machine as, for example, to vary the length of product drop in accordance with changes in the length of the packages being made.
Another object of this invention is to provide a sealing mechanism as described above wherein both of the sealing jaws are movable relative to the frame of the associated machine and when closed meet at the center line of the path of movement of the web through the mechanism so that the web material upon closing of the jaws is not deflected to one side or the other of its normal path.
A still further object of the invention is to provide a sealing mechanism of the foregoing character which may be used either as a stationary unit with the web material being fed by other means therethrough or which may be designed as a reciprocating unit for additional use in pulling or aiding in pulling the web material through the machine.
Other objects and advantages of the invention will be apparent from the following description and from the drawings and claims forming a part hereof.